Camshaft adjusters are used for a targeted adjustment of the phase position between a camshaft and a crankshaft in an internal combustion engine. They allow an optimized setting of valve timing via the engine load and the engine speed. In this way, fuel consumption and exhaust gas emissions may be significantly reduced and the power of the engine may be increased.
A camshaft adjuster is generally made up of a stator, a rotor positioned in the stator, and two sealing covers. A number of pressure chambers, also referred to as vane chambers, are formed in the stator, and are separated from one another by webs which extend radially inwardly away from the stator wall. Rotor vanes of the rotor which is mounted within the stator engage with the pressure chambers. For adjustment of the camshaft, the pressure chambers are acted on by hydraulic medium, as the result of which the rotor is rotated within the stator. Spring elements are often used to move a rotor back into a neutral or starting position during operation of a camshaft adjuster. This requires a secure fastening and position determination of the spring element on the rotor and the stator.
It is known to fasten a coil spring to an inner contour on a spring receptacle, or to needles. However, a spring receptacle is not always usable, for example when a trigger wheel, which is not to be fixedly connected to the camshaft adjuster until the engine is installed, is required. Although fastening to needles is possible in this case, in the individual case it may be necessary to use additional needles, since the coil spring should be relaxed. In this case, problems may arise when a locking mechanism is possibly present, since it is not possible to provide sufficient installation space for the locking mechanism due to the pivot angle of the camshaft adjuster.
A camshaft adjuster of the type mentioned at the outset, which includes a spring element designed as a torsion spring, is known from DE 10 2009 005114 A1. The torsion spring is fastened via its two spring ends to spring retainers provided for this purpose, and is situated between a so-called spring cover plate and the sealing cover, designed as a front cover plate. The spring cover plate is connected to the sealing cover via bolts.
A device for variably setting the timing of gas exchange valves of an internal combustion engine, including a spring element designed as a torsion spring, is known from DE 10 2008 051 732 A1. The torsion spring is situated in a spring chamber, and is fastened via its two spring ends to a sealing cover designed as a side cover. The spring chamber is delimited by a cup-shaped spring cover, for which purpose the spring cover at least partially overlaps the device radially and axially. The spring cover and the sealing cover are fastened to one another via form-fit elements.
DE 10 2010 051 052 A1 provides a camshaft adjuster for an internal combustion engine, including a stator which is connectable to a crankshaft in a rotatably fixed manner, a rotor which is supported in the stator and rotatable about a rotation axis, a sealing cover for minimizing leaks, and a spring element for positioning the rotor with respect to the stator, the spring element being held on the sealing cover via a spring clip in the axial direction and via multiple bolts in the radial direction.
DE 10 2011 082 590 A1 provides a camshaft adjuster which includes a drive element, and an output element which is connectable to a camshaft, and a trigger wheel which is situated coaxially with respect to the rotation axis of the camshaft adjuster, the trigger wheel including a radial tab and an orientation means, the radial tab being provided for fixing the axial position of the trigger wheel with the camshaft adjuster, and the orientation means being provided for fixing the angular position between the trigger wheel and the camshaft.